Improved RTCP decoder

Added detection of KakaoTalk Voice and Chat

1 files changed, 15 insertions, 0 deletions

diff --git a/src/lib/protocols/rtcp.c b/src/lib/protocols/rtcp.c
index 02875648a..f618261dd 100644
--- a/src/lib/protocols/rtcp.c
+++ b/src/lib/protocols/rtcp.c
@@ -35,6 +35,19 @@ void ndpi_search_rtcp(struct ndpi_detection_module_struct *ndpi_struct, struct n
       ndpi_int_rtcp_add_connection(ndpi_struct, flow);
     }
   } else if(packet->udp != NULL) {
+    /* Let's check first the RTCP packet length */
+    u_int16_t len, offset = 0, rtcp_section_len;
+    
+    while(offset < packet->payload_packet_len) {
+      len = packet->payload[2+offset] * 256 + packet->payload[2+offset+1];
+      rtcp_section_len = (len + 1) * 4;
+      
+      if((offset+rtcp_section_len) > packet->payload_packet_len)
+	goto exclude_rtcp;
+      else
+	offset += rtcp_section_len;
+    }
+    
     sport = ntohs(packet->udp->source), dport = ntohs(packet->udp->dest);
     NDPI_LOG(NDPI_PROTOCOL_RTCP, ndpi_struct, NDPI_LOG_DEBUG, "calculating dport over udp.\n");
     if(((packet->payload_packet_len >= 28 || packet->payload_packet_len <= 1200) &&
@@ -45,6 +58,8 @@ void ndpi_search_rtcp(struct ndpi_detection_module_struct *ndpi_struct, struct n
       ndpi_int_rtcp_add_connection(ndpi_struct, flow);
     }
   } else {
+  exclude_rtcp:
+    
     NDPI_LOG(NDPI_PROTOCOL_RTCP, ndpi_struct, NDPI_LOG_DEBUG, "exclude RTCP.\n");
     NDPI_ADD_PROTOCOL_TO_BITMASK(flow->excluded_protocol_bitmask, NDPI_PROTOCOL_RTCP);
   }